JP3871858B2 - Hydrogen recovery device - Google Patents

Hydrogen recovery device Download PDF

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Publication number
JP3871858B2
JP3871858B2 JP2000192047A JP2000192047A JP3871858B2 JP 3871858 B2 JP3871858 B2 JP 3871858B2 JP 2000192047 A JP2000192047 A JP 2000192047A JP 2000192047 A JP2000192047 A JP 2000192047A JP 3871858 B2 JP3871858 B2 JP 3871858B2
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Japan
Prior art keywords
hydrogen
permeable membrane
mass
stainless steel
hydrogen permeable
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JP2000192047A
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Japanese (ja)
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JP2002012403A (en
Inventor
学 奥
皓一 川谷
武志 宇都宮
務 関
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Nippon Steel Nisshin Co Ltd
Tokyo Gas Co Ltd
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Tokyo Gas Co Ltd
Nisshin Steel Co Ltd
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Priority to JP2000192047A priority Critical patent/JP3871858B2/en
Priority to DE60113596T priority patent/DE60113596T2/en
Priority to EP01114270A priority patent/EP1167283B1/en
Priority to KR1020010035634A priority patent/KR20020001561A/en
Priority to US09/891,109 priority patent/US6773472B2/en
Priority to CA002351867A priority patent/CA2351867A1/en
Priority to AU54093/01A priority patent/AU783364B2/en
Publication of JP2002012403A publication Critical patent/JP2002012403A/en
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Description

【0001】
【産業上の利用分野】
本発明は、炭化水素系ガスの熱分解で発生した水素を回収する装置に関する。
【0002】
【従来の技術】
水素は、各種化学工業分野における基礎原料,燃料電池用燃料,熱処理雰囲気用等、広範な用途に使用されており、小規模需要に応じる代表的な製造法としてガス燃料の水蒸気改質が知られている。水蒸気改質で得られる改質ガスは、CO,CO2,余剰H2O等を含んでり、たとえば燃料電池にそのまま使用したのでは、電池性能が阻害される。そこで、改質ガスを燃料電池に供給する前に、CO,CO2,余剰H2O等の副成分を除去することが必要になる。
副成分の除去には、水素を選択透過する作用をもつPd−Ag,Ta等を使用した水素透過膜法がある。水素透過膜は耐熱性多孔体の表面に薄膜として形成されているが(特開昭63−294925号公報,特開平1−164419号公報等)、最近では耐熱性多孔体に代えて多数の孔を空けた金属多孔体の使用が検討されている。
【0003】
水素透過膜法では、たとえば図1に示すように、ジャケット1内に二重管2を配置し、金属多孔体3a及び水素透過膜3bからなる複数の水素分離管3を二重管2の内壁と外壁との間に挿入した後で、Niを担持したアルミナ触媒等の触媒4を二重管2に充填している。水素分離管3に代えて、外面に水素透過膜3bを形成した箱型のメンブレンを使用することもある。
バーナ5からバーナタイル6を経て燃料F及び空気Aを二重管2の内部に送り込み燃焼させる。改質される炭化水素系ガスGは、ノズル7から二重管2の内壁及び外壁との間に水蒸気と共に吹き込まれ、たとえばCH4+2H2O=4H2+CO2の改質反応に従ってH2及びCO2に分解される。
【0004】
生成したH2は、水素分離管3の水素透過膜3bを選択透過し、水素分離管3の内部に流入し、水素取出し口8から取り出される。反応域からH2が水素透過膜3bを介して除去されるため、CH4+2H2O=4H2+CO2の改質反応が促進される。改質反応で生成したCO2は、余剰のH2Oや燃焼排ガスと共に廃ガスWとして排気口9から系外に排出される。
【0005】
【発明が解決しようとする課題】
CH4+2H2O=4H2+CO2の改質反応は、約690℃以上にすると反応が進み、高温になるほど反応速度が速くなる。他方、CO+H2O=CO2+H2の反応は発熱反応であり、707℃以上では反応が進まない。そのため、従来では二重管2の内側がほぼ600〜900℃の高温になるように、且つ温度勾配がつくように、燃料Fの燃焼熱で二重管2を加熱している。
高温雰囲気で使用される材料として汎用ステンレス鋼があるが、水素回収装置の雰囲気は、炭化水素改質用の水蒸気を含んでいる。そのため、SUS410L,SUS430,SUS304等の汎用耐熱ステンレス鋼で作られた金属多孔体3aは容易に酸化され、粒界腐食も進行しやすい。その結果、水素透過膜3bに剥離やクラックが発生し、水素取出し口8から取り出されるH2にC22n+2,H2O,CO2等が混入し、得られる水素ガスの純度が低下する。
【0006】
本発明は、このような問題を解消すべく案出されたものであり、800℃前後の高温雰囲気においても十分な強度を維持する16〜25質量%のCrを含むフェライト系ステンレス鋼を金属多孔体に使用することにより、高温雰囲気で長時間稼動しても性能劣化がない水素回収装置を提供することを目的とする。
【0007】
【課題を解決するための手段】
本発明の水素回収装置は、その目的を達成するため、Cr:16〜25質量%,(C+N)×8以上の含有量でTi及び/又はNbを含むのフェライト系ステンレス鋼からなる基材に複数のガス通過孔を形成し、且つ前記基材の外面に水素透過膜を設けた複数のメンブレンと、外壁と内壁との間に前記メンブレンが挿入され、炭化水素ガス分解触媒が充填されている二重管とを備え、該二重管の内部に送り込まれた燃料の燃焼熱による炭化水素ガスの加熱分解で生成した水素を前記水素透過膜に選択透過させて系外に取り出すことを特徴とする。
【0008】
Ti及び/又はNbは、Ti:0.1〜0.7質量%,Nb:0.2〜0.8質量%の範囲に添加量を調整することが好ましい。また、耐酸化性の改善に有効な希土類元素B族のY及びランタノイド元素の1種又は2種を0.1質量%以下添加することもできる。更には、耐熱性向上に有効なSi,Mn,Al,Mo,Cu,V,W,Ta等を適量添加してもよい。
【0009】
【作用】
600〜900℃の高温で駆動される水素回収装置の雰囲気は、炭化水素系ガスGを改質するための水蒸気を含んでいる。汎用の耐熱ステンレス鋼は不動態皮膜によって優れた耐熱性,耐食性を呈する材料であるが、炭化水素系ガスG改質用の水蒸気や炭化水素系ガスGの分解生成物である水素を含む高温雰囲気に曝されると、水素による不動態皮膜の還元が進行し、水蒸気による酸化,粒界腐食が進行する。酸化や粒界腐食により水素透過膜3bの密着性が低下し、水素透過膜3bに剥離,クラック等が発生しやすくなる。その結果、水素透過膜3bの選択分離膜としての機能が低下する。
本発明者等は、水素分離管3が曝される600〜900℃の水蒸気含有高温雰囲気下における酸化や粒界腐食の挙動を調査・研究した結果、Cr含有量が16〜25質量%のフェライト系ステンレス鋼が金属多孔体3aとして好適な材料であることを見出した。
【0010】
16質量%以上のCrを含むフェライト系ステンレス鋼は、通常の大気雰囲気でCr富化酸化スケール(Cr23又はスピネル)が生成すると十分な耐酸化性を呈する。下地鋼のCr含有量が高くなるほど安定したCr富化酸化スケールが形成されるため、使用限界温度が上昇する。他方、水素回収装置の雰囲気は、多量の水蒸気を含んでおり、ステンレス鋼表面にFe34(外層)及びFe−Crスピネル(内層)の二層スケールを生成させやすい。そのため、大気中の酸化に比較して酸化速度が非常に大きくなる。そこで、本発明においては、Cr含有量を16質量%以上と多くすることにより、Cr富化酸化スケールを安定化し、水蒸気雰囲気中での二層スケールの生成を防止している。水蒸気雰囲気中での耐酸化特性は、Al,Si等の添加によっても改善される。
【0011】
粒界腐食は、マトリックスに固溶しているCrがCと反応してCr系の炭化物を生成することによって生じた粒界のCr欠乏層に沿って腐食が進行する現象である。そこで、Ti及び/又はNbの添加によりCを炭化物,炭窒化物等として固定することにより粒界腐食を抑制する。粒界腐食の抑制効果は、(C+N)×8以上の含有量でTi及び/又はNbを添加することにより顕著となる。Nbは、更に高温強度を改善し、常温〜高温の熱履歴に起因する変形を防止する上でも有効である。このようなことから、Ti及び/又はNbを添加する場合、それぞれの含有量をTi:0.1〜0.7質量%,Nb:0.2〜0.8質量%の範囲に定めることが好ましい。
C,Nの固定に必要なTi,Nbの添加量は、C及びNをそれぞれ0.02質量%以下に低減することにより少なくできる。C,Nの低減は、フェライト系ステンレス鋼の加工性を改善し、複数のガス通過孔を形成して金属多孔体3aを作製する加工も容易になる。
更に、Y,La等の希土類元素を添加することにより、高温強度,高温クリープ特性,耐高温酸化性を改善することもできる。希土類元素の添加効果は、0.01質量%以上で顕著となり、0.1質量%で飽和する。また、高温強度の改善に有効なMo,W,Cu,V,Ta等や、耐高温酸化性に有効なSi,Mn,Al等を適量添加してもよい。
【0012】
Cr含有量が16〜25質量%のフェライト系ステンレス鋼は、水素透過膜3bの熱膨張係数にほぼ等しい点でも水素透過膜3b形成用基材として有利である。たとえば、熱膨張係数が約14×10-6/℃のPd−Ag合金に対し、Cr含有量18質量%のフェライト系ステンレス鋼は約11×10-6/℃の熱膨張係数を示す。熱膨張係数が近似しているため、常温〜高温の熱サイクルを複数回経た後でも熱応力の発生が少なく、水素透過膜3bと金属多孔体3aとの間にクラックが発生しがたい。
このようにして、Cr含有量16〜25質量%以下のフェライト系ステンレス鋼を水素透過膜3b形成用の基材として作製された金属多孔体3aは、水蒸気を含む800℃の高温雰囲気においても、酸化や粒界腐食を生じることなく、十分な強度をもつため、水素回収装置の長時間稼動が可能になる。
【0013】
【実施例】
表1の組成をもつ板厚2.0mmの各種ステンレス鋼を、水素回収装置を想定した水蒸気分圧0.02MPa,温度700℃の高温雰囲気に50時間保持し、耐高温酸化性を調査した。耐高温酸化性は、高温保持後の酸化増量で評価した。粒界腐食は、TIG溶接後に500℃×10時間の熱処理を施した試験片を60℃の硫酸・硫酸銅試験液に浸漬した後、曲げ試験(2t曲げ)後の割れの有無により調査した。
【0014】

Figure 0003871858
【0015】
表2の調査結果にみられるように、本発明例1〜5では、加熱前後で酸化増量が小さく、粒界腐食の発生もみられなかった。これに対し、Ti,Nb等の安定化元素を含んでいない比較材(試験番号6,7)では、何れの鋼種も粒界腐食が発生しており、なかでもCr含有量が低い試験番号7では加熱により著しい水蒸気酸化が発生していた。このようなことから、水素透過膜3bの基材としての要求特性を満足させるためには、Crを16質量%以上とし、且つTi及び又はNbでCを固定する必要があることが判る。
【0016】
Figure 0003871858
【0017】
本発明例2のステンレス鋼板から、孔径0.2mmのガス通過孔11を0.2mmのピッチで複数穿設した金属多孔体12を作製した(図2b)。金属多孔体12の上に膜厚20μmのPd−23質量%Ag薄膜を水素透過膜13として形成した。得られたメンブレン14を箱状枠体15(図2a)の両面に装着し、箱状枠体15に水素取出し管16を接続して表面積100cm2の水素吸収装置10とした。なお、水素吸収装置10としては、箱型に限らず、筒状(水素分離管3:図1)にすることも可能である。
【0018】
水素吸収装置10を二重管2(図1)に組み込み、水素透過特性及び耐久性を調査した。試験条件として、メタン及び水蒸気をそれぞれノズル7から二重管2に送り込み、燃料Fの燃焼によって二重管2を内側から800℃に加熱し、二重管2の内部と水素取出し管16側との圧力差を0.8Paに維持した。炭化水素系ガスGの熱分解で生成した水素は、0.2Nm3/時の割合で水素取出し管16から取り出された。
連続1000時間運転後、二重管2から水素吸収装置10を取り出し、金属多孔体12及び水素透過膜13の性状を調査したところ、運転開始前に比較して何らの劣化も検出されなかった。また、この期間に水素取出し管16から取り出されたH2ガスに含まれるCH4,H2O,CO2等は、1ppm以下に抑えられていた。そのため、得られたH2ガスは、被毒等のトラブルを生じることなく燃料電池用途に使用可能であった。
【0019】
これに対し、比較例のステンレス鋼を金属多孔体12に使用した水素吸収装置10では、1000時間連続運転した時点で水素取出し管16から取り出される水素ガスにCH4,H2O,CO2等が混入するようになった。そこで、二重管2から水素吸収装置10を取り出してみたところ、金属多孔体12の形状が大きく劣化しており、金属多孔体12に積層されている水素透過膜13にもクラックが発生していた。
この対比から明らかなように、本発明に従った水素回収装置は、長時間稼動に十分耐えることが判った。
【0020】
【発明の効果】
以上に説明したように、本発明の水素回収装置は、高温酸化や粒界腐食に対する抵抗力が高く、水素透過膜と同程度の熱膨張係数をもつフェライト系ステンレス鋼を水素透過膜形成用基材として使用している。そのため、水素透過膜が形成されたメンブレンを水蒸気含有高温雰囲気に長時間曝しても高温酸化,粒界腐食,熱応力に起因したクラックの発生等がなく、当初の選択的水素分離性能が維持され、各種化学工業,熱処理雰囲気,燃料電池等の用途に有用な高純度の水素ガスが製造される。
【図面の簡単な説明】
【図1】 水素改質装置の断面構造を示す図
【図2】 本発明実施例で作製した箱型状水素吸収装置の斜視図(a)及びメンブレンの断面図(b)
【符号の説明】
1:ジャケット 2:二重管 3:水素分離管 3a:金属多孔体 3b:水素透過膜 4:触媒 5:バーナ 6:バーナタイル 7:ノズル 8:水素取出し口 9:排気口
10:水素吸収装置 11:ガス通過孔 12:金属多孔体 13:水素透過膜 14:メンブレン 15:箱状枠体 16:水素取出し管[0001]
[Industrial application fields]
The present invention relates to an apparatus for recovering hydrogen generated by thermal decomposition of a hydrocarbon gas.
[0002]
[Prior art]
Hydrogen is used in a wide range of applications such as basic raw materials, fuel cell fuels, and heat treatment atmospheres in various chemical industries, and steam reforming of gas fuel is known as a typical production method that meets small-scale demand. ing. The reformed gas obtained by steam reforming contains CO, CO 2 , surplus H 2 O, and the like. For example, if it is used as it is in a fuel cell, the cell performance is hindered. Therefore, before supplying the reformed gas to the fuel cell, it is necessary to remove subcomponents such as CO, CO 2 and surplus H 2 O.
There is a hydrogen permeable membrane method using Pd—Ag, Ta or the like having an action of selectively permeating hydrogen to remove the subcomponent. The hydrogen permeable membrane is formed as a thin film on the surface of the heat resistant porous body (Japanese Patent Laid-Open Nos. 63-294925, 1-164419, etc.). The use of porous metal bodies with a gap has been studied.
[0003]
In the hydrogen permeable membrane method, for example, as shown in FIG. 1, a double tube 2 is disposed in a jacket 1, and a plurality of hydrogen separation tubes 3 composed of a metal porous body 3 a and a hydrogen permeable membrane 3 b are connected to the inner wall of the double tube 2. After being inserted between the outer wall and the outer wall, the double tube 2 is filled with a catalyst 4 such as an alumina catalyst supporting Ni. Instead of the hydrogen separation tube 3, a box-shaped membrane having a hydrogen permeable membrane 3b formed on the outer surface may be used.
The fuel F and air A are sent from the burner 5 through the burner tile 6 into the double pipe 2 and burnt. The hydrocarbon-based gas G to be reformed is blown together with water vapor between the inner wall and the outer wall of the double pipe 2 from the nozzle 7, and for example, H 2 and H 2 according to the reforming reaction of CH 4 + 2H 2 O = 4H 2 + CO 2. Decomposed into CO 2 .
[0004]
The generated H 2 selectively passes through the hydrogen permeable membrane 3 b of the hydrogen separation tube 3, flows into the hydrogen separation tube 3, and is taken out from the hydrogen outlet 8. Since H 2 is removed from the reaction zone through the hydrogen permeable membrane 3b, the reforming reaction of CH 4 + 2H 2 O = 4H 2 + CO 2 is promoted. CO 2 produced by the reforming reaction is discharged out of the system from the exhaust port 9 as waste gas W together with surplus H 2 O and combustion exhaust gas.
[0005]
[Problems to be solved by the invention]
The reforming reaction of CH 4 + 2H 2 O = 4H 2 + CO 2 proceeds when the temperature is about 690 ° C. or higher, and the reaction rate increases as the temperature increases. On the other hand, the reaction of CO + H 2 O═CO 2 + H 2 is an exothermic reaction, and the reaction does not proceed at 707 ° C. or higher. Therefore, conventionally, the double pipe 2 is heated by the combustion heat of the fuel F so that the inside of the double pipe 2 becomes a high temperature of about 600 to 900 ° C. and a temperature gradient is created.
General-purpose stainless steel is used as a material used in a high-temperature atmosphere, but the atmosphere of the hydrogen recovery apparatus contains water vapor for hydrocarbon reforming. Therefore, the metal porous body 3a made of general heat resistant stainless steel such as SUS410L, SUS430, SUS304, etc. is easily oxidized, and intergranular corrosion is likely to proceed. As a result, peeling or cracking occurs in the hydrogen permeable membrane 3b, and C 2 H 2n + 2 , H 2 O, CO 2, etc. are mixed in H 2 taken out from the hydrogen outlet 8, and the purity of the resulting hydrogen gas is high. descend.
[0006]
The present invention has been devised to solve such a problem. Ferritic stainless steel containing 16 to 25% by mass of Cr, which maintains sufficient strength even in a high temperature atmosphere around 800 ° C., is made of metal porous. An object of the present invention is to provide a hydrogen recovery device that does not deteriorate in performance even when operated in a high temperature atmosphere for a long time.
[0007]
[Means for Solving the Problems]
In order to achieve the object, the hydrogen recovery apparatus of the present invention is a base material made of ferritic stainless steel containing Cr and 16 to 25% by mass and (C + N) × 8 or more and containing Ti and / or Nb. A plurality of membranes each having a plurality of gas passage holes and a hydrogen permeable membrane provided on the outer surface of the base material are inserted between the outer wall and the inner wall, and filled with a hydrocarbon gas decomposition catalyst. A double pipe, wherein hydrogen generated by the thermal decomposition of hydrocarbon gas by the combustion heat of the fuel fed into the double pipe is selectively permeated through the hydrogen permeable membrane and taken out of the system. To do.
[0008]
The addition amount of Ti and / or Nb is preferably adjusted in the range of Ti: 0.1 to 0.7% by mass and Nb: 0.2 to 0.8% by mass. Moreover, 0.1 mass% or less of 1 type or 2 types of rare earth element B group Y and a lanthanoid element which are effective in improving oxidation resistance can also be added. Furthermore, Si, Mn, Al, Mo, Cu, V, W, Ta, etc. effective for improving heat resistance may be added in an appropriate amount.
[0009]
[Action]
The atmosphere of the hydrogen recovery apparatus driven at a high temperature of 600 to 900 ° C. contains water vapor for reforming the hydrocarbon gas G. General-purpose heat-resistant stainless steel is a material that exhibits excellent heat resistance and corrosion resistance due to a passive film, but it contains high-temperature atmosphere that contains steam for hydrocarbon gas G reforming and hydrogen that is a decomposition product of hydrocarbon gas G When exposed to water, the reduction of the passive film by hydrogen proceeds, and oxidation and intergranular corrosion by water vapor proceed. Oxidation or intergranular corrosion reduces the adhesion of the hydrogen permeable film 3b, and the hydrogen permeable film 3b is likely to be peeled off or cracked. As a result, the function of the hydrogen permeable membrane 3b as a selective separation membrane is reduced.
As a result of investigating and studying the behavior of oxidation and intergranular corrosion in a steam-containing high-temperature atmosphere at 600 to 900 ° C. to which the hydrogen separation tube 3 is exposed, the present inventors have found a ferrite with a Cr content of 16 to 25% by mass. It has been found that stainless steel is a suitable material for the porous metal body 3a.
[0010]
Ferritic stainless steel containing 16% by mass or more of Cr exhibits sufficient oxidation resistance when a Cr-enriched oxide scale (Cr 2 O 3 or spinel) is generated in a normal air atmosphere. As the Cr content of the base steel increases, a stable Cr-enriched oxide scale is formed, so that the use limit temperature increases. On the other hand, the atmosphere of the hydrogen recovery apparatus contains a large amount of water vapor, and it is easy to generate a two-layer scale of Fe 3 O 4 (outer layer) and Fe—Cr spinel (inner layer) on the stainless steel surface. Therefore, the oxidation rate becomes very large compared with the oxidation in the atmosphere. Therefore, in the present invention, by increasing the Cr content to 16% by mass or more, the Cr-enriched oxide scale is stabilized and the formation of a two-layer scale in a steam atmosphere is prevented. The oxidation resistance in a steam atmosphere can be improved by adding Al, Si or the like.
[0011]
Intergranular corrosion is a phenomenon in which corrosion progresses along a Cr-deficient layer at the grain boundary caused by the fact that Cr dissolved in a matrix reacts with C to produce a Cr-based carbide. Therefore, intergranular corrosion is suppressed by fixing C as carbide, carbonitride, etc. by adding Ti and / or Nb. The inhibitory effect of intergranular corrosion becomes significant by adding Ti and / or Nb with a content of (C + N) × 8 or more. Nb is further effective in improving the high-temperature strength and preventing deformation due to the thermal history from room temperature to high temperature. For this reason, when adding Ti and / or Nb, the respective contents may be determined in the range of Ti: 0.1 to 0.7% by mass and Nb: 0.2 to 0.8% by mass. preferable.
The amount of Ti and Nb added to fix C and N can be reduced by reducing C and N to 0.02% by mass or less, respectively. The reduction of C and N improves the workability of ferritic stainless steel, and facilitates the process of forming a plurality of gas passage holes to produce the metal porous body 3a.
Furthermore, the addition of rare earth elements such as Y and La can improve high temperature strength, high temperature creep characteristics, and high temperature oxidation resistance. The effect of adding rare earth elements becomes significant at 0.01% by mass or more, and is saturated at 0.1% by mass. Further, Mo, W, Cu, V, Ta, etc. effective for improving the high temperature strength, Si, Mn, Al, etc. effective for high temperature oxidation resistance may be added in an appropriate amount.
[0012]
Ferritic stainless steel having a Cr content of 16 to 25% by mass is advantageous as a base material for forming the hydrogen permeable membrane 3b in that it is approximately equal to the thermal expansion coefficient of the hydrogen permeable membrane 3b. For example, for a Pd—Ag alloy having a thermal expansion coefficient of about 14 × 10 −6 / ° C., ferritic stainless steel having a Cr content of 18% by mass exhibits a thermal expansion coefficient of about 11 × 10 −6 / ° C. Since the thermal expansion coefficients are close to each other, thermal stress is hardly generated even after a plurality of room temperature to high temperature thermal cycles, and cracks are hardly generated between the hydrogen permeable membrane 3b and the metal porous body 3a.
Thus, the porous metal body 3a produced using a ferritic stainless steel having a Cr content of 16 to 25% by mass or less as a base material for forming the hydrogen permeable membrane 3b can be used in a high-temperature atmosphere at 800 ° C. containing water vapor. Since it has sufficient strength without causing oxidation and intergranular corrosion, the hydrogen recovery device can be operated for a long time.
[0013]
【Example】
Various stainless steels having a thickness of 2.0 mm having the composition shown in Table 1 were held in a high-temperature atmosphere having a water vapor partial pressure of 0.02 MPa and a temperature of 700 ° C. assuming a hydrogen recovery device for 50 hours to investigate high-temperature oxidation resistance. The high temperature oxidation resistance was evaluated by an increase in oxidation after holding at a high temperature. Intergranular corrosion was investigated based on the presence or absence of cracks after a bending test (2t bending) after immersing a test piece subjected to heat treatment at 500 ° C. for 10 hours after TIG welding in a 60 ° C. sulfuric acid / copper sulfate test solution.
[0014]
Figure 0003871858
[0015]
As seen in the investigation results in Table 2, in Examples 1 to 5 of the present invention, the increase in oxidation was small before and after heating, and no occurrence of intergranular corrosion was observed. On the other hand, in the comparative materials (test numbers 6 and 7) that do not contain stabilizing elements such as Ti and Nb, intergranular corrosion has occurred in all steel types, and in particular, test number 7 with a low Cr content. In this case, significant steam oxidation was generated by heating. From the above, it can be seen that in order to satisfy the required characteristics of the hydrogen permeable membrane 3b as a base material, it is necessary to set Cr to 16% by mass or more and fix C with Ti and / or Nb.
[0016]
Figure 0003871858
[0017]
A porous metal body 12 in which a plurality of gas passage holes 11 having a hole diameter of 0.2 mm were formed at a pitch of 0.2 mm was produced from the stainless steel plate of Invention Example 2 (FIG. 2b). A Pd-23 mass% Ag thin film having a thickness of 20 μm was formed as the hydrogen permeable membrane 13 on the metal porous body 12. The obtained membrane 14 was mounted on both sides of a box-shaped frame 15 (FIG. 2a), and a hydrogen take-out pipe 16 was connected to the box-shaped frame 15 to obtain a hydrogen absorber 10 having a surface area of 100 cm 2 . Note that the hydrogen absorption device 10 is not limited to a box shape, and may be cylindrical (hydrogen separation pipe 3: FIG. 1).
[0018]
The hydrogen absorption device 10 was incorporated in the double pipe 2 (FIG. 1), and the hydrogen permeation characteristics and durability were investigated. As test conditions, methane and water vapor are respectively sent from the nozzle 7 to the double pipe 2, and the double pipe 2 is heated to 800 ° C. from the inside by combustion of fuel F, and the inside of the double pipe 2 and the hydrogen extraction pipe 16 side are Was maintained at 0.8 Pa. Hydrogen produced by thermal decomposition of the hydrocarbon gas G was taken out from the hydrogen take-out pipe 16 at a rate of 0.2 Nm 3 / hour.
After continuous operation for 1000 hours, the hydrogen absorbing device 10 was taken out from the double tube 2 and the properties of the metal porous body 12 and the hydrogen permeable membrane 13 were investigated. As a result, no deterioration was detected compared to before the operation was started. Further, CH 4 , H 2 O, CO 2 and the like contained in the H 2 gas taken out from the hydrogen take-out pipe 16 during this period were suppressed to 1 ppm or less. Therefore, the obtained H 2 gas can be used for fuel cell applications without causing troubles such as poisoning.
[0019]
On the other hand, in the hydrogen absorbing device 10 using the stainless steel of the comparative example for the porous metal body 12, CH 4 , H 2 O, CO 2, etc. are added to the hydrogen gas taken out from the hydrogen take-out pipe 16 when continuously operated for 1000 hours. Became mixed. Therefore, when the hydrogen absorbing device 10 was taken out from the double tube 2, the shape of the metal porous body 12 was greatly deteriorated, and cracks were also generated in the hydrogen permeable membrane 13 laminated on the metal porous body 12. It was.
As is clear from this comparison, it was found that the hydrogen recovery apparatus according to the present invention sufficiently withstands long-time operation.
[0020]
【The invention's effect】
As described above, the hydrogen recovery apparatus of the present invention uses ferritic stainless steel having a high resistance to high-temperature oxidation and intergranular corrosion and has a thermal expansion coefficient comparable to that of a hydrogen permeable film. Used as a material. Therefore, even if the membrane on which the hydrogen permeable membrane is formed is exposed to a high temperature atmosphere containing water vapor for a long time, there is no generation of cracks due to high temperature oxidation, intergranular corrosion, or thermal stress, and the initial selective hydrogen separation performance is maintained. High-purity hydrogen gas useful for various chemical industries, heat treatment atmospheres, fuel cells and other applications is produced.
[Brief description of the drawings]
FIG. 1 is a diagram showing a cross-sectional structure of a hydrogen reformer. FIG. 2 is a perspective view of a box-shaped hydrogen absorber produced in an embodiment of the present invention (a) and a cross-sectional view of a membrane (b).
[Explanation of symbols]
1: Jacket 2: Double tube 3: Hydrogen separation tube 3a: Metal porous body 3b: Hydrogen permeable membrane 4: Catalyst 5: Burner 6: Burner tile 7: Nozzle 8: Hydrogen outlet 9: Exhaust port 10: Hydrogen absorber 11: Gas passage hole 12: Metal porous body 13: Hydrogen permeable membrane 14: Membrane 15: Box-shaped frame 16: Hydrogen take-out pipe

Claims (2)

16〜25質量%のCr,(C+N)×8以上の含有量でTi及び/又はNbを含むフェライト系ステンレス鋼からなる基材に複数のガス通過孔を形成し、且つ前記基材の外面に水素透過膜を設けた複数のメンブレンと、外壁と内壁との間に前記メンブレンが挿入され、炭化水素ガス分解触媒が充填されている二重管とを備え、該二重管の内部に送り込まれた燃料の燃焼熱による炭化水素ガスの加熱分解で生成した水素を前記水素透過膜に選択透過させて系外に取り出すことを特徴とする水素回収装置。A plurality of gas passage holes are formed in a base material made of ferritic stainless steel containing Ti and / or Nb with a content of Cr, (C + N) × 8 or more of 16 to 25% by mass, and on the outer surface of the base material A plurality of membranes provided with a hydrogen permeable membrane, and a double pipe in which the membrane is inserted between an outer wall and an inner wall and filled with a hydrocarbon gas decomposition catalyst, and is fed into the double pipe A hydrogen recovery apparatus characterized in that hydrogen produced by the thermal decomposition of hydrocarbon gas by the combustion heat of fuel is selectively permeated through the hydrogen permeable membrane and taken out of the system. 更に0.1質量%以下の希土類金属を含むフェライト系ステンレス鋼を水素透過膜の基材に使用している請求項1記載の水素回収装置。2. The hydrogen recovery apparatus according to claim 1, wherein a ferritic stainless steel containing a rare earth metal of 0.1% by mass or less is used as a base material for the hydrogen permeable membrane.
JP2000192047A 2000-06-27 2000-06-27 Hydrogen recovery device Expired - Lifetime JP3871858B2 (en)

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JP2000192047A JP3871858B2 (en) 2000-06-27 2000-06-27 Hydrogen recovery device
DE60113596T DE60113596T2 (en) 2000-06-27 2001-06-12 Gas reformer for the recovery of hydrogen
EP01114270A EP1167283B1 (en) 2000-06-27 2001-06-12 A gas reformer for recovery of hydrogen
KR1020010035634A KR20020001561A (en) 2000-06-27 2001-06-22 A gas reformer for recovery of hydrogen
US09/891,109 US6773472B2 (en) 2000-06-27 2001-06-25 Gas reformer for recovery of hydrogen
CA002351867A CA2351867A1 (en) 2000-06-27 2001-06-26 A gas reformer for recovery of hydrogen
AU54093/01A AU783364B2 (en) 2000-06-27 2001-06-27 A gas reformer for recovery of hydrogen

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